WASHINGTON—The week that Israeli and Palestinian security forces arrested members of a terrorist group linked to millionaire terror mastermind Osama bin Laden, a U.S. report suggested the likelihood of such groups planning attacks against Israel and trying to thwart the peace process.

According to a Congressional Research Service report issued last week, there have been growing signs over the last year that bin Laden might be planning terrorist actions and trying to disrupt the peace process.

Cells operated by bin Laden in Jordan and Lebanon were discovered recently, although no attacks linked to bin Laden were carried out in either country.

The report suggests that guerillas with the militant Islamic group Hamas are gravitating to bin Laden’s network because they fear Hamas might not oppose a Palestinian peace deal with Israel.

Israeli security officials maintain that the 23 activists arrested Monday belong to militant Islamic groups. A Gaza resident was a cell leader and officials say Hamas sent him to Pakistan three years ago to study terror techniques with bin Laden’s organization.

If there is indeed a shifting allegiance of Hamas radicals to join bin Laden’s group, then the threat to Israel and the peace process is significant, said the report’s author.

“This could lead to a very sharp, very sudden upturn in violence,” said Kenneth Katzman, a specialist in Middle Eastern affairs.

Hamas radicals are disillusioned and could be turning to bin Laden because he represents the last bastion of radical ideology and because he has the money to take on anyone, Katzman said.

Bin Laden is estimated to have about $300 million in financial assets with which he funds a network of as many as 3,000 militants, according to the report.

But Hamas so far denies the association with bin Laden, who is accused of masterminding the 1998 U.S. Embassy bombings in Kenya and Tanzania.

“Hamas and I have no connection with bin Laden,” Hamas leader Sheik Ahmed Yassin said last week in Gaza.

Yassin accused Israel of spreading false stories to increase pressure on the Palestinian Authority to act against Hamas.

The report, titled “Terrorism: Near Eastern Groups and State Sponsors,” credits the Palestinian Authority with greater antiterrorism vigilance and taking more pre-emptive actions against terrorists.

The Palestinian Authority seems to be acting on its own without any prompting from Israel, Katzman noted.

The report draws from the State Department’s annual “Patterns of Global Terrorism” report, which was released in April.

Often reports by the Congressional Research Service are prepared at the request of committees or members of Congress. But Katzman said he undertakes the project annually because there is always a lot of interest and the report is widely requested.

Though the report is intended mainly to give background information to lawmakers, if a member of Congress believes findings in the report merit further consideration, he could call for hearings on the subject.

Among the other findings of the report are:

Syria has not stopped anti-Israel attacks by Hezbollah and Palestinian groups in southern Lebanon and continues to give these groups safe haven. Syria also opposed suggestions that Hezbollah be disarmed by U.N. peacekeepers after the militia seized positions in southern Lebanon following the Israeli pullout in May.

Hamas and Palestinian Islamic Jihad terrorism has declined because of increased cooperation between Israeli and Palestinian security forces.